Get raw pecans, break them up lightly just to expose a little extra surface area. Get yourself a bunch of brown lunch bags. Roast the pecans at I think 250 for 15 or so minutes, careful not to burn them. Put them a bag and shake to remove as much oil as possible. Repeat 3-4 times. Let them sit for a couple days to mellow out then add them towards the bottom of your mash. If you're not doing all grain, add them to the last 15 or so minutes of your boil. You'll probably get more flavor if you put them in the boil. I apologize, I don't have my notes in front of me but I'm pretty sure I used about 1lb in a five gallon batch. Do a search for Lazy Magnolia Southern Pecan. That's a good place to start.